Means for preventing fluctuations in rotary motors.



No. 741,290. PA LENTED OCT. 13, 1903.

- J. J. WOOD.

MEANS FOR PREVENTING FLUCTUATIONS IN ROTARY MOTORS.

APPLICATION FILED JULY 16, 1900.

NO MODEL. 2 SHEETS-SHEBT 1.

INVENTOR:

'- WJIg 'LLJESSES: 7i]

1 I By Attorneys, W 6 C mA/au No. 741,290. PATENTED OCT. 13, 1903.

J. J. WOOD. MEANS FOR PREVENTING FLUCTUATIONS IN ROTARY MOTORS.

APPLIGATION FILED JULY 16, 1900.

NO MODEL. 2 SHEETS-SHEET 2.

INVENTOR'.

WITNESSES: E M By Azzameys, W LL ,Patented October 13, 1908..

PATENT O FICE.

JAMES J. WOOD, OF FORT WAYNE, INDIANA, ASSIG-NOR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

MEANS FOR PREVEN TING FLUCTUATIONS lN ROTARY MOTORS $PECIFIC ATIONforming part Of Letters Patent'No. 741,290, dated October 13, 1903.

Appll tration filed July 16, 1900. Serial No. 23.70].- (No model.)

To all whom it may concern:

Be it known that I, JAMES J. WOOD, a citi-' zen of the United States,residing at Fort Wayne, in the county of Allen and State of Indiana,have invented certain new and useful Improvements in Means forPreventingFluctuations in Rotary Motors, of which the following is aspecification.

This invention relates to means for preventing or reducing fluctuationsoccurring in rotary-motor devices-such as steam-engines,

turbines, impact-wheels, orother prime movers-as well as secondary motordevices, such I feeding the motor.

as dynamo-electric machines, electric motors, rotary converters, and thelike. Y

My invention is applicable wherever in such a rotary motor fluctuationsare liable to occur from a uniform rotation by reason either ofvariations in the propulsive energy or variations in the work or load,which'varia- Lions recur at frequent intervals, so that they tend toproduce alternate accelerations and retardations of the motor, such asare known in the art as hunting or pumping.

In my application filed May 31,1900, Serial No. 18,646, I have set fortha. device for preventing such fluctuations, particularly with referenceto synchronous dynamo electric machines, such as alternating motors orrotary converters. In operating such machines the hunting or beatingaction is usually indicative of some irregularity in the circuit Thisirregularity may consist of variationseither in speed or inelectr'omotive force. The variation in speed of the generator tends tocause a corresponding variation in the speed of a synchronous motor. Themotor cannot, however, assume instantly the speed required by the newspeed of the generator. When the speed ofthe generator increases, themotor-armature begins to increase in speed; but by reason of its laggingthe motor receives an increased current, because its armature is not innormal position for the new frequency and because additional currentisrequired for supplying the energy necessary for increasing its speed.This additional current produces a difference of magnetism of the field,which must again 5 0 be altered when the generator speed decreases belowthe average. The motor is therefore seeks to approximate to, but doesnot exactly correspond with, that of the generator. As set forth in mysaid application with particular reference to synchronous alternatingmotors, I overcome this defect and avoid interference with the line byapplying to the shaft of the motor or a shaft rotating therewith afly-wheel of suitable weight, which is yieldingly connected to themotor, .preferably by being free to turn upon its driving-shaft, aspring connectionbeing interposed between undergoing a slight variationin speed, which the fly-wheel and its shaft,so as to oppose relativemovements of the motor and fiy-wheel in either direction. The degree ofsuch relative movement preferahlycorresponds to the angular distancebetween two adjacentpoles of the armature. The spring connection thereinshown comprises a coiled spring or springs interposed endwise betweenabutments formed upon the fly-wheel and its shaft, said springs beingcompactly arranged between these parts and suitable stops being providedfor limiting the strain upon the springs. While well adapted for usewith motors in which the anglebetween the poles 'is not considerable, asis the case with motors having a relatively great number of poles,difiicnlties have been encountered in adapting such devices to mo torshaving comparatively few poles. This is due to the fact that because ofthe relatively great angle between the poles springs of this characterare not well adapted to permit the necessarily extensive rotary movementof the flywheel in a connection which provides the requisitecompactness, durability, and strength.

By my presentinvention I aim to provide ner as to tend to wind or unwindthem. The

springs preferably encircle the axis of rotation of the fiy-wheel andare suitably housed or inclosed, preferably within the fly-wheel.Certain other features of improvement are provided intheconstruction andarrangement of the parts.

In the drawings, in which I have illustrated the preferred form of myinvention,Figu're 1 is aface view of the fly-wheeh partly in section, ontheline 1 1 in Fig. 2. Fig. 2 isadiametrical section of Fig. 1, cut onthe line 2 2; and Fig. 3 is an elevation ofthe locking plugs or keysdetached, the one h beingshown in mid-section; and Figs. tand 5illustrate two applications of my invention to a synchronousdynamo-electric machine.

In the drawings, A indicates a flywheel of any suitable constructionhaving a hub B, Fig. 2, designed to fit loosely upon a sleeve 0, whichis adapted to be keyed or otherwise fixed to a shaft rotating with themotor. rotary electric machines the sleeve 0 is most conveniently keyeddirectlyto the armatu reshaft. lhe fiy-wheelA is mounted to turn freelyupon its sleeve 0, except that suchroshown as an involute, and is fixedat one end to the fly-wheel A and at its other end to the sleeve 0, andthe springs are preferably re- .versely arranged, so that each is woundor unwound by such relative movement. It is characteristic of thepresent invention that the spring or springs are so arranged thatrelative movements of the fly-wheel and motor tend to wind or unwind thesprings. Such springs are best arranged so that they encircle the axisof rotation of the fiy wheel, preferably as shown, by embracing theshaft of the motor.

Any suitable. means may be provided for connectingthe ends of thesprings to the flywheel and shaft; but I prefer that shown, because ofthe convenience. in putting such springs under the requisite tension.The flywheel A is formed with a flange "E which extends parallel withthe sleeve 0, and with such sleeve forms anannular recess F, adapted toreceive the springs D D. The flange E is formed at a suitable pointonits inner face with a recess e, within which is fixed a pin or stud e,

which serves to engage the outer ends of the springs, the latter beingformed with a hook or eye encircling the pin. The inner-ends of thesprings D D are preferably fastened to the sleeve 0 through the mediumof rings G G. The use of these rings is not essential, but considerablysimplifies the assembling of the parts. Each of the rings G G is formedwith a slot g, which receives the inner end of its spring, the latterbeing bent to form a hook entering this slot, as shown in Fig; 1. Eachring is formed along its inner face with a series of semicircularrecesses g, which in the circular recess thus formed. necessary that anystress be imparted to the when the ring is turned upon the sleeve 0successively register with a similar recess 0, formed in the outer partof the latter.

' in assembling the outer end of the spring D is engaged with the stud eand its inner end with the ring G, and the latter is adjusted so thatone of its recesses g registers with the recess a of the sleeve, when aheadless bolt or plug 71, Figs. 2 and 3, is inserted It is not spring Dat this time. The spring D is fixed to the stud e' and its ring G, andthe latter is rotated relatively to the sleeve 0 and flywheel until therequisite degree of compression is given to both springs, whereupon thenearest recess 9 is brought into coincidence with the recess 0 of thesleeve, and the sleeve and ring are then fixed together by insertion ofa plug or key it. To provide for readily accomplishing thiscompressionof the springs, I form the ring G with diametrically opposite recessest', which are adapted to receive a spanner or similar tool. Upon removalof the spanner thesleeve will rotate backwardly until the tension of thesprings is equalized. This method of assembling has the advantage thatit is not necessary to hold the sleeve rigid during compression of thesprings, and the provision of the recesses g and-c affords a means foreasily connecting the springs to the sleeve and for adjusting to anicety the degree of compression best suited for resisting the relativemovement of the fly-wheel and sleeve in each particular instance.

inorder to secure the parts firmly in place, I preferablyscrew-threadthe end of the sleeve 0, as shown atj, and provide a collar i-I, adaptedto screw thereon. The collar is formed with a semicircular recess in inits hub, which registers with alike recess 0', forming a continuation ofthe recess a of the sleeve C, when the collar is set tight on thelatter. When the two recesses and c are brought into coincidence, theyconstitute a cylindrical socket,

which is screw-threaded, and into which is screwed a plug 1. Primarilythe function of the plug lie to constitute a .key for locking the collarH in place upon the sleeve; but in the device shown I also utilize,it tohold the plugs h and h firmly in place. Each of these plugs is formedwith a screw-threaded socket m, Fig. 3, to receive a suitable threadedtool, so that the plug may be easily withdrawn when necessary by firstremoving the screwplug it. A

It'will be observed that the springs are completely housed by the collarH and flange E. The freedom of movement of the fly-wheel relatively toits shaft may inv the construction thus far described be limited only bythe degree of compression of the springs. When used with rotary electricmachines, it is desirable, if. not essential, that this relativemovementshall be such that if the fly-wheel were held stationary the,armature could be rotated from onev pole to the next. Preferably it isdesirable in orderto prevent overstraining of the springs to providesome mechanical stops for limiting the movement in case it shouldgreatly exceed the normal, and such stops may be provided by forming aflange O on the end of the sleeve 0 with a lug p, which may encounter arib q, Fig. 2, formed on the iiy-wheel, the rib and lug being providedat any suitable angular distance, so as to give the desired amount offree movement before they come into contact.

' It will be noted that the character of connection provided by mypresent invention permits a great relative movement of the flywheel andits shaft, so that my device is especially adapted for'use with machinesof but few poles, such as two-pole or four-pole machines, althoughapplicable to those having a greater number, if desired. Theconstruction provided by me is exceedingly strong and durable, while incompactness it compares favorably with the connection before referredto.

My invention is applicable to any form of motor device wherein theenergy applied to it or that derived from it is fluctuating, so that therotary device is subject to alternate acceleration and retardation, andthereby produces the effect known as hunting or pumping. It isspecifically adapted to synchronous alternating motors and rotaryconverters.

For the purpose of illustrating one of the applications of my inventionI have shown in Figs. 4 and 5 two modes of applying my improved deviceto a synchronous dynamo-electric machine. In these figures, I indicatesan alternating-current motor or other synchronous dynamo-electricmachine of a wellknown four-pole type,J its armature, and Kits shaft.Such motors are well known and need not be further described. In Fig. 4the fiywheel A is mounted directly upon the armatureshaft K. This is notessential, however,

i as the shaft of the fly-wheelmay be any shaft connected to the motorand rotating therewith. Thus in Fig. 5 I have shown the motor as beltedto a counter-shaft K and the flywheel A mounted on this shaft, in whichconstruction the same results are attained. It will also be understoodthat the spring connection provided by my invention need not be directlybetween the fly-wheel and its shaft, but maybe interposed at any pointbetween the motor and fiy-wheel, so long as the described results areattained.

By the term fly-wheel as used in. this specification I include notmerely such a wheel as a mechanic would ordinarily understand by thisterm, but also any suitably symmetrical mass or masses so mounted andadapted as to act in a manner substantially equivalent to the action ofa fly-wheel-that is to say, by rotating with the motor and by reason ofits inertia resisting any acceleration or retardation of its normalspeed of rotation.

My invention is to be distinguished from those structures wherein aspring connection is employed as the means through which load or workcarried thereby. Such means for yieldinglytransmitting power areincapable of overcoming the effects of hunting or pumping. In theapplication of my inven tion the fly-wheel is essentially idle, formingordinarily no part of the means through which power is transmitted, sothat the function of its springs is confined solely, or substantiallyso, to the taking up of any relative fluctuations in the speed betweenthe fly-wheel and motor. .I therefore designate the flywheel of myinvention as an idle fiy-wheel, in the sense that no work, or at leastno substantial part of the work performed by the motor, is transmittedthrough it- I do not hereby mean to exclude the possibility that suchidle flywheel may at times be made the means through which work may beperformed by the motor, it being well understood that with, for example,a synchronous alternating motor there is practical freedom from anyhunting effect when carrying a considerable load, the action known ashunting occurring chiefly when the motor is run practically withoutload, at which time .alone my invention is especially desirable forapplication to such mo= tor, and it is sufiicient that under suchcircumstances the fly-wheel shall become an idle fly-wheel in the senseherein indicated.

1 claim as my invention the following-defined novel features,substantially as herein- ,before specified, namely:

1. The combination with a rotary motor, and an idle fly-wheel driventhereby, free to turn relatively thereto, of a spring connection betweenthe two adapted to resist in either direction fluctuations in theirrelative speeds,

eomprising a spiral spring arranged to be wound or unwound by relativemovements of said parts and means receiving the reaction of said spring.

2. iihe combination with a rotary dynamoelectric machine, and an idlefly-wheel driven thereby, free to turn relatively thereto, of a springconnection between the two adapted to resist in either directionfluctuations in'their relative speeds, comprising a spiral springencircling the axis of rotation of said fiy-wheel, and arranged to bewound or unwound by relative movements of said parts and means receivingthe reaction of said spring.

EEO

3. The combination with a rotary motor,

and a fly-wheel driven thereby, free to turn relatively thereto, of aspring connection between the two comprising two reversely-arrangedspiral springs adapted to be wound and unwound by relative'movements ofsaid fly-wheel and motor.

4. The combination with a rotary motor,

and a fly-wheel driven thereby, free to turn relatively thereto, of aspring connection between the two comprising two reversely-ar rangedspiral springs encircling the axis of ro- 7 power is communicated from amotor to the tation of said fly-whee'l, whereby to resist relativemovementsof said fiy-wheel and motor.

5. The combination with a rotary motor, and a fiy-wheel driven thereby,free to turn relatively thereto,of a connectiorrbetween the twocomprising two reversely-arranged involute springs each wound uponitself, and each engaged at its endsby the fly-wheel and motorrespectively.

6, The combination with a rotary motor,

and a 'fiy-wheel driven thereby, free to turn relatively thereto,of aconnection between the two comprising two reversely-arranged involutesprings each wound upon itself, and each encircling the axis of saidfly-wheel, whereby to resist relative movements of said fly-wheel andmotor.

7. The combination with a rotary motor, and a fly-wheel driven thereby,free to turn relatively thereto,of a connection between the twocomprising an involute spring connected to the fiy-wheel at itsouterend, means for adjusting the stress of said spring comprising anadjustable ring connected to the motor and engaging the inner end ofsaid spring, and means receiving the reaction of said spring.

8. The combination with a rotary-motor, and a fiy-wheel driven thereby,free to turn relatively thereto,of a connection between the twocomprising two reversely-arrange'd involute springs each connected tothe fiy-wheel at its outer end, and two rings connected to the motor andengaging the inner ends of said springs, and relatively adjustable toadjust the stress of said springs.

9. The combination with a rotary motor, of a. shaft rotating therewith,a sleeve carried by said shaft, a fly-wheel free to turn on said sleeve,and two reverselyarranged spiral springs encircling said sleeve andconnected thereto at their inner ends, and to the flywheel at theirouter ends.

10. The combination with a rotary motor,'of a shaft rotating therewith,a sleeve carried by said shaft, a fly-wheel free to turn on said sleeve,two rings encircling said sleeve, and two reversely-arranged spiralsprings each encircling one ofsaid rings and connected thereto at itsinner end, and each connected to the fly-wheel at its outer end.

- 11. The combination with a rotary motor,of a shaft rotating therewith,a fly-wheel free to turn on said shaft, a ring encirclingsaid shaft, aspiral spring encircling said ring, and means receiving the reaction ofsaid spring, said spring connected to said fiy-wheel and, ring, and saidshaft andring each having a recess,

1 and adapted to be moved to bring such recesses into coincidence,whereby the stress upon said spring may be adjusted byrotating saidring, and inserting a plug in said recesses, when the latter coincide.

' 12. The combination with a rotary motor,of

a shaft rotating therewith, a sleeve fixed to said shaft, 2. fly-wheelfree to turn on said sleeve, a ring encircling said sleeve, a spiralspring encircling said ring, andmeans receiving the reaction of saidspring, said-spring connected to said fly-wheel and ring, and saidsleeve and ring each formed with a recess, and'adapted to be moved tobring such recesses into coincidence, whereby the stress upon saidspring may be adjusted by rotating said ring, and insertinga plugin saidrecesses when the latter coincide;

13. The combination with a rotary motor,of a shaft rotating therewith, asleeve fixed "to said shaft,a fly-wheel free to turn on said sleeve, 9.ring encircling said sleeve, a spiral spring'encircling said ring, saidmeans receivin g the reaction of said spring, said spring connected tosaid fly-wheel and said ring, and said sleeve and ring formed the onewith a plurality of recesses and the other with a recess, said partsadapted to be moved to bring such recesses into coincidence, whereby thestress upon said spring may be adjusted by rotating said ring, andinserting a plug in sleeve, inner and outer rings encircling saidsleeve, and spiral springs encircling said rings, said springseachconnected to said fly-weeel and one of said rings, said sleeve formedwith arecess, and said outer ring with a plurality oft recesses, wherebythe stress upon said springs may be adjusted by rotating said outerring, and inserting a plug in said recesses in the ring and sleeve whensuch recesses coincide.

15. The combination with a rotary motor,of a shaft-rotating therewith, asleeve fixed to said shaft, a fly-wheel' free to turn on said sleeve,inner and outer rings encircling said sleeve, and spiral springsencircling said rings, said springs each connected to said flywheel andone of said rings, said sleeve formed with a recess, and said outer ringwitha plurality of recesses, whereby the stress .upon ,said springs maybe adjusted by rotating said outer ring,and insertingaplug in saidrecesses in the ring and sleeve when such recesses coincide, and acollar screwing on said sleeve and having a recess adapted to be broughtinto alinement with said recess in the sleeve,

and a plug screwing into said alined recesses.

- In witness whereof I have hereunto signed my name in the presence oftwo subscribing witnesses.

4 JAMES J. WOOD. Witnesses: A

E. J. KING, W; F. MELEHING.

